I use the Lee Auto-prime hand tools. In the interest of safety I only put 20 primers at a time in the tray, usually. My max is 25 at one time if I am loading lots of 50 or 100 cases.
Something I have only noticed with the tool set up for the small primers: once in a while a primer will bounce up on edge on the seating bolt and try to seat sideways. I caught a couple before exerting much force. That seems a good way to induce a discharge. Now I visually inspect for proper presentation before I give the handle a squeeze. It just takes a split second to check.
Scott,
It sounds like you had an exciting experience. I am glad you came out okay.
